This paper analyzes the social impact of the 1877-1878 Mega-Niño event in Costa Rica, through the comparison of data about droughts, rains, locust plagues and epidemics, collected from documentary sources of that time, with analysis of meteorological data. During the years 1877-1878, Central America was dominated by drier, warmer and windier conditions, like the ones observed during a warm El Niño event in the eastern equatorial Pacific. That scenario did not favor the formation of mesoscale convective systems on the Central American Pacific slope, nor the formation of tropical cyclones in the Atlantic basin, what is in agreement with the drier observed conditions.